This invention features a compound of the following formula: T-(-L-C).sub.m,T is a transportophore, L is a bond or a linker having a molecular weight up to 240 dalton, C is a non-antibiotic therapeutic agent, and m is 1, 2, 3, 4, 5, 6, 7, or 8, in which the transportophore has an immune selectivity ratio of at least 2, the transportophore is covalently bonded to the non-antibiotic therapeutic agent via the bond or the linker, and the compound has an immune selectivity ratio of at least 2.